SusChEM: Collaborative Research: Holey Reduced-Graphene-Oxide Film for Na-Ion Battery Anode

主要研究者：Hu，Liangbing / Barone，Veronica提案编号：1335979 /1335944机构：马里兰州大学帕克分校/中密歇根大学标题：合作研究：用于钠离子电池阳极的多孔还原氧化石墨烯膜由于钠的低成本和地球丰度，钠离子电池（NIB）正在成为一种可行的技术，以满足运输和其他储能应用的要求。合理的结构设计，允许有效地操纵电子和离子的多孔电极是至关重要的。虽然Na在地球上比Li丰富得多，但Na离子具有更大的尺寸，这对Na离子技术提出了巨大的挑战。在过去的几年里，人们对钠离子电池的兴趣越来越大。最近报道了用于阴极、阳极和电解质的新材料。其中包括Na_（2/3）Mn_（1/2）Fe_（1/2）O_2、Na_（0.44）MnO_2和NaMPO_4（M=Fe，Ca，Mn）等。对于阳极电极，硬碳显示出250 mAh/g的容量，但具有差的倍率和循环性能。高性能、低成本的负极材料是钠离子电池成功的关键。二维碳材料是有前途的，因为Na离子插入平面中以实现高度可逆的容量;然而，在用于Na离子电池的二维碳材料中存在挑战。目前还没有成功的工作电极演示，也没有对钠离子存储机制的基础研究，本项目将结合实验和计算工具来研究和识别三种可能的钠离子存储机制：钠离子嵌入、团簇形成和与官能团的氧化还原反应。基本的电荷存储动力学也将进行研究。基于多孔还原氧化石墨烯（H-RGO）的合理纳米结构将被设计用于高性能钠离子电池阳极，利用其基本的电荷存储机制。H-RGO的初步实验详细介绍了这一建议，显示出有希望的结果为目标的应用。控制实验的结果与基于密度泛函理论的初步计算预测吻合得很好。实验和计算的共同努力将克服基于碳纳米材料的钠离子电池阳极的根本挑战。与锂离子电池相比，钠离子电池需要更好的材料设计和电化学科学来实现类似的存储容量（热力学）和速率性能（动力学）。该项目的重点是材料结构和与H-RGO纳米结构中Na离子操作相关的基本原理。材料设计、缺陷处理、纳米级离子空穴传输、插层势垒、与官能团的相互作用、Na团簇形成等，将通过理论，计算和实验之间的协作和协同方法进行彻底研究。从实用的角度来看，所提出的原子水平的理解将促进阳极材料的优化，以通过利用H-RGO的大表面积并控制其化学性质，在高电流密度率下实现类似于锂离子阳极所提供的Na比容量。碳材料作为阳极的成功示范，加上阴极材料的最新发展，将使低成本的钠离子技术用于能源储存成为可能。这将允许将太阳能和风能纳入可再生能源领域。这项研究将被整合到研究生和本科课程中，目的是吸引学生在职业生涯的早期进入该领域。在协作环境中的研究也将为本科生和研究生提供解决实验和计算问题的机会。

PI: Hu, Liangbing / Barone, VeronicaProposal Number: 1335979 / 1335944Institution: University of Maryland College Park / Central Michigan UniversityTitle: Collaborative Research: Holey Reduced-Graphene-Oxide Film for Na-Ion Battery AnodeDue to the low cost and earth abundance of sodium, Na-ion batteries (NIB) are emerging as a viable technology to meet the requirements for transportation and other energy storage applications. Rational structure designs that allow effective manipulation of electrons and ions in multiporous electrodes are critical. Although Na is much richer on earth than Li, Na ion has a much larger size, which poses grand challenges for Na-ion technologies. There has been an increasing interest on Na ion batteries in the past few years. Novel materials for cathodes, anodes, and electrolytes were recently reported. A few promising cathode materials are demonstrated, such as Na2/3Mn1/2Fe1/2O2, Na0.44MnO2 and NaMPO4 (M=Fe, Ca, Mn). For the anode electrode, hard carbon is shown to present a capacity of 250 mAh/g, but with a poor rate and cycling performance. High-performance and low cost anode materials are still needed for the success of Na-ion batteries. Two-dimensional carbon materials are promising as Na ions intercalate in the planes to achieve a highly reversible capacity; however, challenges exist in 2D carbon materials for Na-ion batteries. There is neither a successful demonstration of working electrodes, nor fundamental studies of Na ion storage mechanisms.In this project, experimental and computational tools will be combined to investigate and discern the three possible Na ion storage mechanisms: Na ion intercalation, cluster formation, and redox reactions with functional groups. Fundamental charge storage kinetics will also be studied. Rational nanostructures based on holey reduced graphene oxide (H-RGO) for high-performance Na-ion battery anodes will be designed by exploiting their fundamental charge storage mechanisms. Preliminary experiments on H-RGO detailed in this proposal, show promising results for the targeted applications. Results on controlled experiments agree well with preliminary computational predictions based on density functional theory. The proposed joint effort from experiments and computation will overcome the fundamental challenges in Na-ion battery anodes based on carbon nanomaterials.Much more challenging than Li-ion batteries, Na-ion devices require better materials design and electrochemistry science to achieve similar storage capacity (thermodynamics) and rate performance (kinetics). This project focuses on the materials structure and fundamentals related to the manipulation of Na ions in H-RGO nanostructures. Materials design, defects manipulation, nanoscale ion transport through holes, intercalation barriers, interactions with functional groups, Na cluster formation, etc., will be thoroughly investigated through a collaborative and synergistic approach between theory, computation, and experiments. From a pragmatic viewpoint, the proposed atomic level understanding will facilitate the optimization of anode materials to achieve Na specific capacities at high current density rates similar to the ones offered by Li-ion anodes, by exploiting the large surface area of H-RGO and controlling its chemical nature.The successful demonstration of carbon materials as anodes, coupled with the recent development of cathode materials, will enable the use of low-cost Na-ion technologies for energy storage. This will permit the incorporation of solar and wind energy into the renewable energy landscape. The research will be integrated in both graduate and undergraduate courses with the goal of attracting students to the area early in their careers. Research in a collaborative environment will also give undergraduate and graduate students opportunities to solve problems from both experiments and computations.